High Step-Up DC–DC Converter With Galvanic Isolation for Distributed Power Generation

This paper presents a new isolated DC-DC converter that integrates a coupled inductor, a transformer, and the voltage multiplier technique to achieve a high voltage gain. The proposed topology offers three degrees of freedom for voltage gain adjustment: the turns ratio of the coupled inductor (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N_a</i>), the turns ratio of the transformer (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N_b</i>), and the duty cycle (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i>). Using these parameters, the converter can achieve the desired voltage gain with flexibility. In addition, it ensures high efficiency while minimizing voltage and current stress on the components. Theoretical evaluations of the operating principle are presented, demonstrating that some semiconductors achieve ZCS during turn-ON or turn-OFF. Modeling and closed-loop control are also evaluated, demonstrating good performance. Additionally, a comparative evaluation with similar topologies is presented. Finally, a prototype was built in the laboratory, achieving a maximum efficiency of 97.53%.